Sort an array by value/key - mix of string and numeric values PHP

Question

I need to sort an array. Both values and keys are the same and are strings. Basically, array looks similar to this:

 $test = array(
      '1' => '1',
      '2' => '2',
      '1.5' => '1.5',
      '3' => '3',
      '4' => '4',
      '3.5' => '3.5',
      '2XS' => '2XS',
      '2XL' => '2XL',
      'XXL' => 'XXL',
    );

Expected Output:

 Array
 (
     [0] => 1
     [1] => 1.5
     [2] => 2
     [5] => 3
     [6] => 3.5
     [7] => 4
     [3] => 2XL
     [4] => 2XS
     [8] => XXL
 )

Any ideas?

I tried natural sorting with sort() basically so that won't be of much help. I'm a complete noob at this. — dodo254
– dodo254, Commented Apr 12, 2017 at 12:07

Sahil Gulati · Accepted Answer · 2017-04-12 11:58:25Z

4

PHP code demo

<?php 
$test = array(
      '1' => '1',
      '2' => '2',
      '1.5' => '1.5',
      '3' => '3',
      '4' => '4',
      '3.5' => '3.5',
      '2XS' => '2XS',
      '2XL' => '2XL',
      'XXL' => 'XXL',
    );
$numericArray=array();
$stringsArray=array();
array_map(function($value) use (&$numericArray,&$stringsArray) {
        if(is_numeric($value))
        {
            $numericArray[]=$value;//Here we are putting numeric values
        }
        else
        {
            $stringsArray[]=$value;//Here we are putting string values
        }

}, $test);
sort($numericArray,SORT_NUMERIC);//sorting on numeric basis
sort($stringsArray,SORT_REGULAR);//sorting on string basis
$result=array_merge($numericArray,$stringsArray);//merging both of them
print_r($result);

Output:

Array
(
    [0] => 1
    [1] => 1.5
    [2] => 2
    [3] => 3
    [4] => 3.5
    [5] => 4
    [6] => 2XL
    [7] => 2XS
    [8] => XXL
)

answered Apr 12, 2017 at 11:58

Sahil Gulati

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3 Comments

nerdlyist Over a year ago

Why not just foreach? array_map make this way more complicated then it needed.

Sahil Gulati Over a year ago

@nerdlyist Yes it is correct that i could use foreach but usually i use array_map. The above result can be achieved from different methods. but i followed this and thats not an issue.

Sahil Gulati Over a year ago

@nerdlyist It can be a case if anyone is not familier with array_map than after seeing this that person will learn a new function :)

RomanPerekhrest · Accepted Answer · 2017-04-12 12:10:05Z

1

The solution using usort, is_numeric and strcmp functions:

usort($test, function ($a, $b) {
    if (is_numeric($a) && is_numeric($b)) {
        return $a - $b;
    } else if (is_numeric($a) && !is_numeric($b)) {
        return -1;
    } else if (!is_numeric($a) && is_numeric($b)) {
        return 1;
    } else {
        return strcmp($a, $b);
    }
});

print_r($test);

The output:

Array
(
    [0] => 1
    [1] => 1.5
    [2] => 2
    [3] => 3
    [4] => 3.5
    [5] => 4
    [6] => 2XL
    [7] => 2XS
    [8] => XXL
)

answered Apr 12, 2017 at 12:10

RomanPerekhrest

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Comments

nerdlyist · Accepted Answer · 2017-04-12 12:21:36Z

1

<?php
$test = array(
    '1' => '1',
    '2' => '2',
    '1.5' => '1.5',
    '3' => '3',
    '4' => '4',
    '3.5' => '3.5',
    '2XS' => '2XS',
    '2XL' => '2XL',
    'XXL' => 'XXL',
);

function sortNandS($array){
    $nums = [];
    $strings = [];

    foreach($array as $elm) {
        is_numeric($elm) ? $nums[]= $elm : $strings[]=$elm;
    }
    sort($nums,SORT_NUMERIC);
    sort($strings,SORT_REGULAR);
    $result=array_merge($nums,$strings);

    return $result;
}

print_r(sortNandS($test));

edited Apr 12, 2017 at 12:21

answered Apr 12, 2017 at 11:57

nerdlyist

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1 Comment

nerdlyist Over a year ago

There is absolutely nothing wrong with @SahilGulati solution and this is very similar just with a function and foreach

mickmackusa · Accepted Answer · 2022-09-21 13:00:19Z

0

More efficiently than any previously posted answer, use array_multisort(). By passing an array of is_numeric() return values as the first parameter, your script will enjoy a lower time complexity because the is_numeric() calls will be n. Comparatively, usort() will be calling is_numeric() 2 * n log n (which is less efficient).

Code: (Demo)

array_multisort(
    array_map('is_numeric', $test),
    SORT_DESC,
    $test
);

If you want to see what the usort() equivalent looks like: (Demo)

usort(
    $test,
    fn($a, $b) => [is_numeric($b), $a] <=> [is_numeric($a), $b]
);

Unlike uasort() and array_multisort(), usort() will re-index the array after modifying it.

answered Sep 21, 2022 at 13:00

mickmackusa♦

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